Viking Horns Loud 149 decibels 4 trumpet Train Sound Air Horn. Made of Triple Chrome Plated metal to withstand all weather conditions. Comes with a 1 gallon (4 liter) air tank, 150 PSI 12 volt heavy duty Air compressor, air pressure gauge, air pressure switch, hose, mounting hardware, and a FREE horn button. Air horn will produce a loud train sound at 149 decibels, and surely will get anybody's attention around you. Can be installed on the roof or at engine compartment or under the vehicles carriage. Great for Cars, SUV, Trucks, RV's, Pick-Ups, Marine and Boats, and many other applications. Horn trumpets dimensions: 16-3/4", 14-3/4", 11-3/4", 9-1/4". Air Tank/compressor dimensions: 7-3/4" L x 8-1/2" H x 8-1/2" W.